Novel gamma, delta unsaturated aldehydes

ABSTRACT

There are provided novel gamma, delta-unsaturated aldehydes of the general formula:   WHEREIN R1 is alkyl of 1-9 carbon atoms or alkenyl of 2-9 carbon atoms, R2 and R3 are hydrogen or alkyl of 1-6 carbon atoms, R4 is hydrogen, alkyl of 1-6 carbon atoms or alkenyl of 2-6 carbon atoms, and R5 and R6 are hydrogen or methyl. These novel compounds possess a floral or fruity aroma. There are also provided novel processes for preparing said compounds.

United States Patent [191 Lainparsky Nov. 18, 1975 NOVEL GAMMA, DELTAUNSATURATED ALDEHYDES [75] Inventor: Dietmar Lamparsky,

Wangen-Dubendorf, Switzerland [73] Assignee: Givaudan Corporation,Clifton, NJ.

[22] Filed: Apr. 16, 1970 [21] Appl. No.: 29,258

[30] Foreign Application Priority Data Cresson, P., Bull. Soc. Chim.France, 1964, pp. 2618-2628.

Marbet et al., I-Ielv. Chim. Acta, Vol. 50, pp. 2095-2100, 1967.

Eschenmoser, A., Chemical Abstracts, Vol. 70, pg. 380, Item No. 88l08v,1969.

Primary Examiner.lames 0. Thomas, Jr. Assistant ExaminerR. I-I. LilesAttorney, Agent, or Firm-Thomas Cifelli, Jr.

[5 7] ABSTRACT There are provided novel gamma, delta-unsaturatedaldehydes of the general formula:

wherein R is alkyl of l-9 carbon atoms or alkenyl of 2-9 carbon atoms, Rand R are hydrogen or alkyl of 1-6 carbon atoms, R is hydrogen, alkyl ofl-6 carbon atoms or alkenyl of 2-6 carbon atoms, and R and R arehydrogen or methyl.

These novel compounds possess a floral or fruity aroma. There are alsoprovided novel processes for preparing said compounds.

2 Claims, No Drawings NOVEL GAMMA, DELTA UNSATURATED ALDEHYDES v RELATEDAPPLICATIONS I This application claims priority from Swiss patentapplication Ser. No. 6405/69 filed Apr. 26, 1969.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The novel7,6-unsaturated aldehydes of the present invention have the followinggeneral formula (I):

wherein R, is alkyl of 1-9 carbonatoms or alkenyl of 2-9 carbon atoms,R, and Rg are hydrogen or alkyl of 1-6 carbon atoms, R is hydrogen,alkyl of 1-6 carbon atoms or alkenyl of 2-6 carbon atoms and R and R,are hydrogen or methyl. These compounds possess utility as odorantshaving a floral or fruity odor, or flavorants having a fruity taste.While the aroma of these compounds is not limited thereto, a citruscharacter predominates.

The compounds of formula (I) are produced by reacting a secondary allylalcohol or general formula, (II) I in the presence of an acidiccatalyst, with an aldehyde enol ether (Illa) of the corresponding acetal(lllb) wherein R, and R -R are as above and, R and R 'are alkyl of l.-4carbon atoms.

If desired, the reaction can take place in a'solvent, at

elevatedtemperature s, or under pressure or subject to a combinationthereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compounds of the presentinvention are odorants and flavorants of general Formula (I.)

The substituents on the hept-4-en-l-al skeleton are hydrogen, alkyl oralkenyl, and they may be the same or different, branched chain orstraight chain.

In the starting materials (II, Illa, and lllb) and the final product(I), R is alkyl or, alkenyl, for example methyl, ethyl, n-propyl,iso-propyl, n-butyl, sec-butyl, iso-butyl, pentyl, hexyl, heptyl, octyl,nonyl, vinyl, allyl, butenyl, such as l-butenyl or 3-butenyl,3-methyl-butenyl, pentenyl, hexenyl such as l-hexenyl or 2-hexenyl,heptenyl or the like. R and R are hydrogen or alkyl having the samevalues as R up to 6 carbon atoms, R, is hydrogen, alkyl or alkenylhaving the same values as R up to 6 carbon atoms, and R and R arehydrogen or methyl.

The compounds of the present invention are pre- ,pared by condensing anallyl alcohol of general formula en-3-ol, l-penta-decen-3-ol,2-octen-4-ol, 2-nonen-4- ol, 7-methyl-l-octen-3-ol,4-methyl-l-hexen-3-ol, 8- methyl-] ,7-nonadien-3-ol, 4,8-dimethyl-l,7-nonadien- 3-ol, 6-methyl-l-hepten-3-ol, and 1-tetradecen-3-ol.

Among the enol ethers of formula (llla).which may be. employed in thereaction are, for example, the following substances: vinyl methyl ether,vinyl ethyl ether,

propen-l-yl ethyl ether, Z-methylpropen-l-yl ethyl ether. v g v Usefulas the acetalsof formula (lllb) are, for example: acetaldehyde diethylacetal, propionaldehyde diethyl acetal, propionaldehyde dimethyl acetal,isobutyraldehyde diethyl acetal,5-methyl-4-hexenyl diethyl acetal andoenanth-aldehyde acetal- The catalyst employed may be an organic orinorganic acid. In the former category, oxalic acid, trichloraceticacid, and p-toluene sulfonic acid may be especially mentioned. The lastof these is particularly preferred. As inorganic acids there may bementioned mineral acids such as phosphoric or sulfuric acids.

In carrying out the process of thepresent invention, it is preferred toreact the active starting materials, in

the absence of a solvent, although the reaction may also be carriednoutin the presence of solvents. The desirable solventsare reaction inertsolvents, suitably hydrocarbon solvents such as hexane, cycle-hexane,isooctane, benzene, toluene, petroleum ether, ligroin and the like.

The quantity of solvent-used is not critical.

Asnoted above; two types of reactants may be employed with the allylalcohol (II), namely, enol e thers (Illa); and acetals-(lllb).

unsaturated aldehyde (I) as well as a reusable by-product as shownbelow: a

. 4. spheric pressure are'of course longer, suitably between about'tafindiabout*8 hours.,The exact time depending on whether the enol ether(llla) or the acetal (lllb) are used as starting material.

The given reaction'times'ar'e intendeds olely as general guides., lt hasbeen .found .most useful to.-run-.test

O OH (1)+Ron .-l

2 R R4 R3 R4 III (1112.) a) R (II) pyrolysis R It will be seen that theby-product, acetal (V), is substantially similar to acetal (lllb). Itmay thus be used in the manner of acetal (lllb) described below, or itmay be reconverted to enol ether (llla) by cleavage of the elements ofthe alcohol ROl-l, suitably by pyrolysis or other means well known tothose skilled in the art.

ln the second modification of the process there are used between 0.5 and1 moles of acetal (lllb) per mole of allyl alcohol (II). In thismodification it has been found most helpful to remove the alcohol formedfrom the reaction mixture by continuous distillation, suitably by meansof .an advantageously arranged fractionation column.

lnboth of the above modifications there are utilized between 0.01 and0.1, preferably between 0.02 and 0.05% by weight of acid catalyst basedonthe charged reactants.

The reaction is carried out by mixing the reactants and catalyst andcausing them to react at elevated temperatures and, desirably atelevated pressures.

The reaction should be carried out at temperatures above- C, preferablyabove C, most preferably at between and 250C.

Where the reaction is to be carried out at atmospheric pressure, one ofthe above named solvents may be used. The reactants may be heated underreflux with or without the presence of solvent.

' It has been found most convenient to carry out the reaction underpressure in an autoclave. The pressure may be generated by the surchargeof an inert gas, for example, nitrogen or the like. The operatingpressure is not critical; initial surcharges of from l-lO atmospheres,suitably about 5 atmospheres have been found desirable. An initialpressure of 5 atmosphereswill rise to about 11-14 atmospheres at about C(internal reaction-vessel temperature) and will fall to between about9-12 atmospheres on completion of the reaction at the same temperature.

Reaction times, using the autoclave method, are of the order of up to 3hours, usually about 2 hours, after an initial warmup time of about 30minutes, to reach the operating temperature. Reaction times atatmobatches and to follow the composition of the reaction 30 mixture bygas chromatographic analysis in order to de- 35 However, it does notreadily lend itself to fractional separation during the course of thereaction. Such'se'paration is important for the maintenance of a properreaction equilibrium where the acetal (lllb) is employed. While use ofthe acetal (lllb) is withinthe 40 scope of the invention, productivityconsiderations thus weigh heavily in favor'of the use of'the enol etherllla).

'In addition to the batch processes mentioned above,

the process of the present invention may be carried out continuously. Inthis modification thereaction" mixture is passed through a tube heatedto elevated temperatures and kept under pressure.

It is advisable to determine the optimal reaction conditions foreach.reaction mixture within the range of the parameters.

After completion of the reaction by any of the previously describedembodiments, the reaction product (I) is separated, suitably byfractional distillation of the reaction product. Prior to thedistillation step, itis advantageous to neutralize the acid catalyst.This neutralization is achieved by adding a'small amount'of an organicor inorganic base 'to the reaction mixture. Bases such as sodiumacetate, sodium hydroxide, sodium carbonate, ammonia, and tertiaryamines such as' triethylamine or pyridine may be employed. The base maybe added directly to the reaction mixture, which is then washed withwater to substantial neutrality, dried and then dis-' carrot, celery andcinnamon odors, of especial interest is a compound having a melon-typearoma.

Certain of the novel compounds of the present invention are of especialinterest. Among these interesting compounds may be mentioned: 4-decenalwhich has a strong orange character coupled with a flowery, lily of thevalley with lilac odorant note; 2-methyl -4-decenal, 3-methyl-4-decenaland 8-methyl-4-nonenal similarly have a fruity character with a citrusnote, while 2,6- dimethyl-4-octenal is of consequence due to its melonnote.

[t is to be understood that the compounds named herein include alloptical and conformational isomers includable under the terminologyutilized.

In the following Examples, the temperatures are stated in degreescentigrade.

EXAMPLE 1 4-Decenal l-Octen-3-ol (44g) and 15 mg of p-toluenesulphonicacid are treated with 74 g of vinyl ethyl ether at The reaction mixtureis stirred at room temperature for 30 minutes and then transferred intoa suitable pressure vessel.

Nitrogen at 5 kg/cm is charged to the autoclave which is heated to 180internal temperature (bath temperature 220) within 30 minutes. In sodoing, the pressure rises to 11 to 12 atmospheres, but then, withconstant internal temperature, falls to ca 9 atmospheres. The saidinternal temperature is maintained for 80 minutes. The autoclave isthereafter quenched,

the reaction mixture neutralized with sodium carbonate, washed withwater, dried and distilled.

4-Decenal (46g) is obtained; boiling point 94 to 95l14 mm Hg, N 1.4421to 1.4432, purity ca 94%.

The aldehyde has a very strong odour which is reminiscent of citrusfruits especially oranges.

EXAMPLE 2 4-Dodecenal 1-Decen-3-ol (14.2g) is cooled to 0, treated withstirring with 5 mg of p-toluenesulphonic acid and subsequently with 19.6g of vinyl ether. The reaction mixture is stirred at room temperaturefor 30 minutes,.th'en decanted into a pressure vessel and, under anitrogen pressure of 5 kglcm placed in a pre-heated bath of 220. After20 minutes, the necessary internal temperature of 175180 is reached.This temperature is held for 90 minutes, and the pressure rises to ca 12kglcm while the pressure falls to the value of 8 to 9 kglcm Afterquenching the autoclave with ice-water, the reaction mixture isneutralized and worked up as in Example I. There are obtained 10 g of4-dodecenal of boiling point 74/0.3 mm Hg, n 1.4460.

This aldehyde has a fresh citrus odor.

EXAMPLE 3 4-Tetradecenal 1-Dodecen-3-o1 (65.4g), mg ofp-toluenesulphonic acid and 76.4 g of vinyl ethyl ether are mixedtogether as in Example 1 and 2 and subsequently heated to an autoclaveinternal temperature of 180, under an initial nitrogen charge at apressure of 5 kglcm for 2 hours. After quenching the pressure vessel andworking up the reaction mixture as in Examples 1 and 2, there areobtained 49 g of 4-tetradecenal of boiling point 123/1 mm Hg. n 1.4498.The odor of this aldehyde is reminiscent of fir-cones and fresh linen.

EXAMPLE 4 3-Methyl-4-Nonenal l95,-under an initial nitrogen charge at apressure of 5 kg/cm for 2 hours as in the preceding Examples. Afterquenching and working up the reaction mixture as in Examples l-3, theremay be obtained 10 g of 3- methyl4-nonenal of boiling point 32/0.02 mmHg, n 1.4387. The odor of this aldehyde is citrus-like and fruity (applejuice).

EXAMPLE 5 3-Methyl-4-Decenal 2 -Nonen-4-ol, (383g) obtained froml-bromopentane and crotonaldehyde by means of a Grignard reaction ismixed with 12 mg of p-toluenesulphonic acid and 58 g of vinyl ethylether as in Example 1. After transferring the mixture into a pressurevessel, 5 kg/cm of nitrogen are charged thereto. The autoclave is thenheated to an internal temperature of within 20 minutes, whereby thepressure rises to 14 kglcm The temperature of 190 is maintained for 2hours, then the autoclave is 190 is maintained for 2 hours, then theautoclave is quenched and after opening the autoclave the reactionmixture is neutralized washed, dried and distilled in accordance withthe procedures of Examples 1 and 2. There are obtained 19.1 g of3-methyl-4- decenal of boiling point 63/0.05 mm Hg, n 1.4419. Thisaldehyde has a fresh odour reminiscent of orange peel.

EXAMPLE 6 2-Methyl-4-Decenal l1 .5'kg/cm After working up as in theExamples 1 and 2 described hereinbefore, there are obtained 28.7 g of2-methyl-4-decenal of boiling point 52/0.07 mmHg, n 1.4358.

The odour of this aldehyde is citrus-like and slightly soapy.

EXAMPLE 7 2,3-Dimethyl-4-Nonenal 2-Octen-4-ol (44g) is treated asdescribed hereinbefore with 15 mg of p-toluenesulphonic acid and 86 g ofpropenyl ethyl ether, stirred and transferred to a pressure vessel aftercharging nitrogen, at 5 kglcm the autoclave is heated to within 20minutes. This temperature is maintained for 2 hours, whereby thepressurerises to from between 10 and 12 kg/cm and falls to about 1 1.8kg/cm towards the end of the reaction. After working up as described inexamples 1 and 2, there are obtained 41.5 g of 2,3-dimethyl-4-nonenal ofboiling point 46/0.5 mm Hg; n 1.4404.

The odour of this aldehyde is reminiscent of freshly scraped carrots.

EXAMPLE 8 EXAMPLE 10 2,2-Dimeth l-4-Decenal Fruit Green Composition withWoody Undertone 1-Octen-3-o1, (23 g) is treated with 70 mg ofcrystallized phosphoric acid, and 17 g of isobutyraldehyde di- Pam bywelgh ethyl acetal are added with stirring and the mixture is 4.D 1 70held at reflux for 4 hours under a nitrogen atmosphere. 5322:31 3? 1% 8The reflux condenser is subsequently replaced by a L f g8 Methanolsuitable pac ked fractlonatmg column and the heating 10undecylenealdehyde 10% of the reaction mixture 111 the nitrogen streamcontm- Benzyl acetate ued. In the course of 3 hours, ethyl alcoholdistils off at Pine needle oil 150 an internal flask temperature risingfrom 98 to 180. fim'g :8 The reaction mixture is taken up in 100 ml ofether Hydrqxycitronellal 30 and, as described above, neutralized,washed, dried, gz yg 2g freed from solvent. The crude product (22g) isfraccedzrwood on Amflic' 5o tionally distilled whereby initially ca 8 gof unreacted a-Methylionone 5g 1-octen-3-ol and subsequently ca 6 g of2,2-dimethy1-4- 3:23? i decenal (boiling point 52/0.1 mm Hg; n 1.4393) Tpass over. A further 1.3 g of the said aldehyde are con- 20 tained inthe end-fraction distilling at 56/0.1 mm Hg. The odor of this aldehydeis green, humus-like; back- EXAMPLE 11 ground of aldehyde note remmlscemof celery Flowery Composition with Predominant Aldeh dic y EXAMPLE 9 pNote N r u the ume o s o r y 6 unsaturated aldehydes may be Pans byweight prepared by the general processes of examples 1 and 2.

Certain of these aldehydes are set forth in Table I 4-Tefladecenal 10%below preceded by the enol ether (Illa) or acetal (111b) i-ggggm-gg gzg'3g and the allyl alcohol (ll) utilized in their preparation. 30Decylaldehyde 10% 10 TABLE 1 ENOL ETHER (llla) ALLYL ALCOHOL7,8-UNSATURATED OR ACETAL (lllb) (11) ALDEHYDE (l) bpC mml-lg nODOR-FLAVOR 1 l-propenyl ethyl l-decen-3-ol 2-methy1-4-dodecenal 91 0.41.4461 green aldehydie ether 2 l-propenyl ethyl 1-hexen-3-o12-methyl-4-octenal 72 12 1.4345 green fatty. when diether lute,orange-like 3 l-propenyl ethyl 2-methyl-1-hexen- 2.4-dimethyl-4-octena]12 1.4420 waxy, light floral.

ether 3-01 green 4 isobutyraldehyde di- 1-hexen-3-o12,2-dimethy1-4-octena1 37 0.2 1.4343 green, fruity, light ethyl acetalfatty 5 vinyl ethyl ether 5-nonen-4-o1 3-propy1-4-octenal 68 0.7 1.4473green, geranium-like,

light animal note 6 l-propenyl ethyl 4-methyl-1-hexen-2,6-dimethy1-4-octena1 77 13 1.4349 fruity melon ether 3-01 7 heptanaldiethyl 1-hexon-3-o1 2-pentyl-4-octena1 75 0.15 1.4459 fruity, mandarinorange acetal peel-like 8 vinyl ethyl ether fi-methyl-l-hepten-8-methyl-4-nonenal 42/4 0.5 1.4409 fruity, aldehydic 95-methyl-4-hexena1 4-methy1-1-hexen- 2-(3-methy1-2 125 0.2 1.4770 herb,undertone of diethyl acetal 3-ol butenyl)-6 methyl-4- cinnamylesteroctenal 1'hexen3-ol 2-pentyl-2-(2-hexenyl) 113 0.05 1.4640 oily,flavorant for 10 heptanal diethyl acetal -4-octenal animal feeds 1 1isovaleraldehyde di- 2-hepten-4-ol 2-iso-propyl-3-methyl- 55-57 0.051.4485 fatty acid ester type ethyl acetal 4-octenal odor, reminiscent ofenanthic ether 12 vinyl ethyl ether 8-methyl-1,7- 10-methyl-4,9-un- -920.05 1.4651 citrus fruit type nonadien 3-ol decadienal odor, aldehydic13 6-methy1-5-heptena1 4-methyl-l- 2 (4-methy1-3'-penteny1) 0.1 1.4590green, flowery, remidiethyl acetal hexen-S-ol -6-methyl-4-octenal 107niscent of acetophenone 14 l-propenyl ethyl 4,8-dimethyl-1,2,6,10-trimethyl-4,9- 76 0.4 1.4667 green, flowery, remiether7-nonadien-3-ol undecadienal niscent of acetophenone or hydratropicaldehyde, but milder -continued -continued Parts by weight Parts byweight undecylenealdehyde 1% 50p-tert.Butyl-a-methylhydrocinnam-aldehyde 5O Styrallyl ace atLinalylacetate 120 Amy sa|icy|ate 15 5 G eranyl acetate Bergamot oilReggie 2o Cltronellol 5o Mandarin oil 20 Nonan-l,3-diol-monoacetate 50Orange n [ML 20 Betanaphthyl ethyl ether 20 Citronellol 50 Indole 5phenyhnhyl alcohol 50 Anthranillc acid methyl ester 5 Hyd y i ll l 5oPetitgram o|l Paraguay l0 Phenylethylmethylethylcarbinol 100 0 Jasmineblossom oil artificial I50 960 Ylang ylang oil 20 a-lononea-Methylionone 70 lsoeugeonol l0 Ethyllinalool 45 EXAMPLE l3 Sandalwoodoil East Ind. 15 h Vetiveryl acetate Eau De Cologne-Type CompositionResinoicl Olibanum 20 Pentadecanolide 20 Benzyl salicylate 50 Parts byweight woo 8-Methyl-4-nonenal 5 20 Bergamot oil synthetic 360 Bergamotoil Reggio l Lemon oil Italian 135 Orange oil Californian I90 Petitgrainoil Paraguay 90 EXAMPLE 12 Methyl-betanaphthyl ketone cryst. 10 Fl l odom 0 i Cinnamic acid methyl ester 10 C p of Fresla Type Aroma 25Resinoid Benzoe Siam l0 Lavender oil Mont Blanc 35 Parts by weight 9' Arggraml igsclil methylester l0 2.4-Dimethyl-4-octenal 10% in PSDE 3oHydroxycitmneual 300 iethylenglyco monoethyl ether 85 Phenylethylalcohol80 Methyl jonon alpha 70 3O Rosewood oil (brazilian) 80 Ylang Ylang OilBourbon 10 i claim: l,l ,4.4-Tetramethyl-6-ethyl-7-acetyl- 1.2-Methyl-4-decenal. l,2,3.4.-tetrahydronaphthalene l0 2. 4trans-Decenal.l-leliotropin 20 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3,920, 752 Dated November 18, 1975 Inventor( D1 QtmBT'Lamparqky It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 44, "alcohol or general formula" should read alcohol ofgeneral formula Column 1, line 65, (IIIb) is omitted under the secondstructure.

Column 2, line 36, "l-hexen-3-ol l-hepten" should read l-hexen-3-ol,l-hepten Column 3, line 2, "enol ether." should read enol ether Signed.and Sealed this twenty-ninth Day Of June 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissionernj'Parerits and Trademarks

1. 2-METHYL-4-DECENAL.
 2. 4TRANS-DECENAL.